Substations play a crucial role in power transmission and distribution systems. They are an integral part of the power grid and serve as a hub for interconnecting different grid sections. Substations are primarily used to transform, switch, and distribute electrical power from high- and low-voltage levels. They are classified based on their insulation methods, and two commonly used types are air-insulated substations (AIS) and gas-insulated substations (GIS). The main difference between AIS and GIS is their insulation medium. This article will discuss in detail the differences between AIS and GIS.
Air-Insulated Substation (AIS)
Air-insulated substations (AIS) are the most commonly
used type of substation. They use atmospheric air as the insulation medium
between the conductors and the ground. AIS is typically used in areas with abundant land and a favorable environment. In an AIS, the
electrical equipment is placed in the open air, and the conductors are
supported by insulators. The substations are designed to withstand environmental conditions like rain, wind, and temperature fluctuations.
AIS is relatively cheaper and easier to construct and
maintain than other substations. However, they occupy a large area and
require considerable space for the equipment and associated
switchyards. AIS is also less reliable in areas with harsh weather conditions,
such as areas with high pollution or coastal regions.
Gas-Insulated Substation (GIS)
Gas-insulated substations (GIS) are a relatively newer
technology than AIS. They use high-density gas, such as SF6, as the
insulation medium between the conductors and the ground. GIS is typically used in
urban areas with limited space and harsh environments. The
substations are designed to withstand environmental conditions like humidity, pollution, and extreme temperature fluctuations.
GIS occupies a much smaller area than AIS, requiring less
space for the equipment and associated switchyards. They also provide better
reliability and require less maintenance than AIS. However, GIS is more
expensive to construct than AIS due to the cost of the insulation medium and
associated equipment.
Comparison between AIS and GIS
The table below summarizes the key differences between
AIS and GIS.
|
Feature |
Air-Insulated Substation (AIS) |
Gas-Insulated Substation (GIS) |
|
Insulation medium |
Atmospheric air |
SF6 gas |
|
Environmental conditions |
Suitable for areas with mild weather
conditions |
Suitable for areas with harsh weather
conditions |
|
Footprint |
Large area required for equipment and
switchyards |
Smaller area required for equipment and
switchyards |
|
Reliability |
Less reliable in harsh weather conditions |
More reliable in harsh weather conditions |
|
Maintenance |
Requires more maintenance |
Requires less maintenance |
|
Cost |
Less expensive to construct |
More expensive to construct. |
Conclusion
Substations are a critical component of the power grid,
and their design and construction depend on various factors, such as the
environment, available space, and budget. AIS and GIS are the two most commonly
used types of substations, and the choice between them depends on the project's specific requirements. While AIS is less expensive and easier to
construct, it is less reliable in harsh weather conditions and requires more
maintenance. On the other hand, GIS is more costly but provides better
reliability and requires less maintenance.
Reference:
Amarnath, C., Ramkumar, M., & Ashok, M. S. (2015). A
review of comparison of GIS and AIS substation. 2015 IEEE Power, Communication
and Information Technology Conference (PCITC), 231-236. doi:
10.1109/PCITC.2015.731